Drinking Straw

ABSTRACT

A drinking straw having a tubular member made of a plastic, having an interior passage that provides fluid communication between an inlet end for immersing into a beverage and a draw end for placing between the lips of a user; and a multipore member, disposed within the tubular member along a portion of the length of the tubular member, having a plurality of passageways extending from an inlet end to the draw end of the multipore member. The multipore member is typically plastic and formed of a plurality of individual flow tubes that communicate between the inlet end and draw end of the multipore member.

FIELD OF THE INVENTION

The invention is in the field of drinking straws, specifically for hot or cold beverages.

BACKGROUND

Hot beverages are commonly consumed by people and include tea, hot chocolate and coffee drinks. While warm beverages can be drunk without problem, hot beverages can scald and burn the mouth and lips. Nevertheless, the advantages of producing and dispensing hot beverages in containers permits dispensing the beverage after preparing it, without waiting for it to cool or cooling it, and extends the temperature of the beverage for a longer period of time. Another problem with hot beverages is the potential for tipping and spilling of the beverage, which can burn or scald the skin of the user.

To prevent or limit the chance of spillage of the hot beverage, the container can be fitted with a lid that contains the beverage. The lid typically has an opening, typically a reclosable opening, through which the beverage can be sipped. Nevertheless, the hot beverage can still scald and burn the mouth and lips.

Similarly, very cold beverages that are drunk at the low temperatures or at high draw volumes can overly chill the mouth, and sometimes can cause a “brain freeze” headache.

SUMMARY OF THE INVENTION

The present invention relates to a drinking straw comprising: a tubular member made of a plastic, having an interior passage that provides fluid communication between an inlet end for immersing into a beverage and a draw end for placing between the lips of a user; and a multipore member, disposed within the tubular member along a portion of the length of the tubular member, having a plurality of passageways extending from an inlet end to the draw end of the multipore member.

The present invention further provides a drinking straw having a tubular shape that has a greater pressure drop of the liquid beverage for a given beverage flow rate, or conversely, a reduced beverage flow rate through the drinking straw for a given pressure drop, relative to a conventional drinking straw of the same tubular size. This can prevent the person drinking through the straw from drawing in excessive amounts of the high-temperature, or cold-temperature, beverage, into the mouth.

The invention also provides a drinking straw comprising a tubular member having an internal diameter, and a multipore member that has a substantially greater liquid passage surface area through its cross section, relative to the tubular member, that provides a greater heat transfer area with the beverage liquid as it passes through the passageways of the multipore member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of the drinking straw of the present invention with a portion of the tubular member cut away and having plurality of individual flow tubes.

FIG. 2 shows a second embodiment of the drinking straw of the present invention with a portion of the tubular member cut away, and having plurality of individual flow tubes and a non-porous portion disposed within a cross section of the tubular member.

FIG. 3 shows another embodiment of the drinking straw of the present invention with a portion of the tubular member cut away and having a microporous multipore member.

FIG. 4 shows another embodiment of the drinking straw of the present invention with a portion of the tubular member cut away and having a multipore member having a plurality of confronting, closely-spaced plates.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a drinking straw for drinking hot and cold beverages. The straw has an outer tubular surface, which typically resembles a conventional cylindrical drinking straw, and a corresponding inner tubular surface. The inner straw has an passage defined by the inner tubular surface has an obstructed portion that obstructs the flow of the beverage that is being drawn through the straw.

The obstructed portion provides a means for reducing the cross sectional area for flow of the beverage. Reduction of the total cross section area results in a lower flow rate of beverage drawn through the obstructed portion and the drinking straw, as compared to a conventional straw having the same inner tubular surface size when drawing with the same drawing (sucking) pressure.

The obstructed portion also provides a means for reducing the effective diameter or cross sectional area of each of the plurality of passageways formed in or by the obstructed portion. The effective diameter of the passageway is the size of the largest sphere within the passageway. A plurality of passageways with reduced effective diameters or cross sectional area, in total, will more greatly reduce or obstruct the flow of beverage at a given drawing pressure compared to a single passageway having the same total cross sectional area. The plurality of reduced-area passageways require an increased pressure differential for a given flow rate. This means that the user must draw the beverage up the straw with greater drawing pressure in order to achieve the same flow rate of beverage as compared to a conventional straw of the same outer tube size. The effective diameter of the passageway is typically about 25% or less of the diameter of the straw, more typically less than 15%, and even more typically less than 10%. Typically the user must draw with at least 50% more pressure (vacuum) than with only a conventional straw, for a given flow rate, more typically at least 100% more pressure, and more typically at least 300% more pressure.

Further, the obstruction provides a means for moving heat from, or moving heat to, the beverage, from the material from which the obstructed portion is made. In effect, the obstruction can serve as a heat sink. Hot beverages being drawn through the obstruction will transfer heat into the obstructed portion. Conversely, cold beverages being drawn through the obstructed portion will draw heat from the obstructed portion. This amount of heat transferred is proportional to the surface area of the plurality of passageways in the obstruction. The amount of heat withdrawn from the beverage as it passes through the straw will depend on several factors, including, but not limited to, the amount of surface area within the passageways, the flow rate, the inlet temperature of the beverage, the heat transfer coefficient of the straw material. Typically the temperature drops at least 1° C., more typically about 2-5° C.

A benefit of the invention is that a person drinking hot beverages, such as store-bought coffee, hot chocolate, and tea, will less likely draw too much hot beverage, too quickly, into the mouth. The drinking straw of the present invention can serve to restrict the rate of flow of the beverage through the straw, or withdraw heat out of the beverage and into the obstruction (consequently, reducing the temperature of the beverage that enters the mouth), or both.

The obstructed portion typically comprises a multipore member which is formed within the inner tubular passage of the outer tubular member. The multipore member can be integrally formed with the tubular member, or can be a discrete element that is inserted and secured therein. The multipore member has a plurality of pores or passageways, much like capillaries, that communicate across the multipore member from an inlet end to an outlet or draw end. Each pore or capillary can be a discrete passageway along the length from the inlet end to the outlet end, or it can intersect with, join, and split off from other passageways along the length. The pore or capillary can have any shape, such as circular, elliptical, oval, rectalinear, and irregular, and can have a different cross sectional shape at various positions along the length of the straw.

The multipore member can be configured to extend any portion of the length along the inner surface of the tubular member. Multiple multipore members can be formed into one straw along its length. The multipore member can be configured to extend across the entire interior cross section of the tubular member. The multipore member can also be configured to extend across one portion, or across several portions, of the cross section of the tubular member. Typically, the remaining portions are closed off with a wall or other non-porous, non-fluid communicating, member.

One embodiment of the drinking straw and multipore member is shown in FIG. 1, showing the drinking straw 10 having an outer tubular member 12 and a multipore member 20. The tubular member 12 resembles a conventional drinking straw, having an inner surface 14, a draw end 16 and an inlet end 18. The multipore member 20 is shown disposed intermediate the draw end 16 and the inlet end 18 of the tubular member 12, but can be positioned proximate either end. The multipore member 20 is shown as a plurality of elongated tubules 22, each individually having an inlet end 24 and a draw or outlet end 26 oriented toward the inlet end 18 and draw end 16 of the tubular member 12, respectively, and which define a small diameter capillary or passageway 32. The typical internal passage defined by the inner surface 14 is about 3-7 mm in diameter, and the typical passageway 32 is about 0.1 to 1 mm in effective diameter. The plurality of tubules 22 are typically bundled to prevent relative movement, and are typically fixed in position along the length of the tubular member 12. Alternatively, the plurality of tubules 22 can be formed integrally, such as by extrusion of the plastic material. While FIG. 1 shows approximately 25 individual tubules, the number of tubules and their capillaries can vary depending upon the thickness of the tubule wall 30 of each tubule and between tubules, the effective diameter of the tubules, the length of the tubules, as well as the desired reduction in the amount of liquid flow for a given drawing pressure (vacuum).

Another embodiment of the drinking straw and multipore member is shown in FIG. 2. This drinking straw 110 resembles the one shown in FIG. 1, but provides that a portion of the cross section of the tubular member 12 is occupied by at least one non-porous member 40. The non-porous member 40 can be a solid member, or can be hollow. The non-porous member 40 can extend the length of the tubules 22, or can be substantially planar, adjacent one end 26, or the other end 24, or anywhere along the length of, tubules 22. FIG. 2 shows a single non-porous member 40 disposed inside or a ring of tubules 22. There can also be a plurality of the non-porous members, and the non-porous member can be disposed around a central bundle of tubules 22. Essentially any sort of arrangement of the non-porous member 40 with the tubules 22 can be made, including randomly and in a pattern.

A further embodiment of the drinking straw and multipore member is shown in FIG. 3. The drinking straw 210 has a multipore member made from a microporous structure. The microporous structure typically has randomly arranged capillaries that split and join with other numerous other capillaries, passing from one end of the microporous structure to the other. A typical example of the microporous structure can be found the sintered microporous plastic disclosed in U.S. Pat. No. 6,030,558, the disclosure of which is incorporated herein by reference.

Another drinking straw and multipore member is shown in FIG. 4. The drinking straw 310 has a multipore member 320 comprising a plurality of confronting, closely-spaced plates 60. The confronting plates 60 can be joined intermittently along their widths at joints 62. The gap 64 between confronting plates is typically between 0.05 to 0.5 mm.

The obstruction or micropore member, can be made of any suitable material, including plastic, ceramic, and metal. Typical plastic materials include polyethylene terephthalate (PET), (high density) polyethylene, polypropylene, and polycarbonate. The plastic can be the same type as used in making the outer tubular member, or different. The plastic used to form the obstruction is preferably flexible and non-friable to avoid breakage and splintering. Preferred for hot beverages is a plastic that designed for use with hot to boiling temperatures, to minimize softening of the plastic and possible extraction of compounds within the plastic into the hot beverage. Other materials include metal materials, typically aluminum. 

1. A drinking straw consisting of: a tubular member made of a plastic, having an interior passage that provides fluid communication between an inlet end for immersing into a beverage and a draw end for placing between the lips of a user; and a plastic multipore member, disposed within and across the entire interior cross section of the interior passage tubular member along a portion of the length of the tubular member, having a plurality of passageways through which the beverage flows, extending from the inlet end to the draw end of the multipore member.
 2. (canceled)
 3. The drinking straw of claim 2 wherein the multipore member comprises a plurality of individual flow tubes that communicate between the inlet end and draw end of the multipore member.
 4. The drinking straw of claim 6 wherein the multipore member comprises a microporous structure that communicates between the inlet end and draw end of the multipore member.
 5. The drinking straw of claim 1 wherein the multipore member is in cylindrical form, to be inserted within the passage of the tubular straw member.
 6. The drinking straw of claim 1 wherein the multipore member is formed integrally with the tubular member.
 7. The drinking straw of claim 1 wherein the multipore member further comprises a non-porous portion disposed within the cross section of the tubular member.
 8. The drinking straw of claim 7 wherein the multipore member comprises a plurality of individual flow tubes that communicate between the inlet end and draw end of the multipore member.
 9. The drinking straw of claim 1 wherein the multipore member comprises a microporous plastic structure that communicates between the inlet end and draw end of the multipore member.
 10. The drinking straw of claim 3 wherein the multipore member comprises at least three passageways.
 11. The drinking straw of claim 8 wherein the multipore member comprises at least three passageways.
 12. The drinking straw of claim 10 wherein the multipore member comprises at least ten passageways.
 13. The drinking straw of claim 1 wherein the multipore member comprises at least ten passageways.
 14. The drinking straw of claim 1 wherein the multipore member comprises a plurality of confronting, closely-spaced plates.
 15. (canceled)
 16. (canceled)
 17. The drinking straw of claim 1 wherein the tubular member has an outer surface that is cylindrical.
 18. The drinking straw of claim 17, wherein the effective diameter of the plurality of passageways is less than 25% the diameter of the tubular member.
 19. The drinking straw of claim 18, wherein the effective diameter of the plurality of passageways is less than 10% the diameter of the tubular member.
 20. (canceled)
 21. The drinking straw of claim 4, wherein the effective diameter of the plurality of passageways is less than 25% the diameter of the tubular member.
 22. The drinking straw of claim 21, wherein the effective diameter of the plurality of passageways is less than 10% the diameter of the tubular member. 